Disable the Windows MessengerThis creates far more problems than it solves.
Right click the taskbar and click the Task Manager. In the Task Manager, click
the Processes tab.
On the Processes tab, click the Image name column header. You'll notice that
this arranges program names in alphabetical or reverse alphabetical order. This
prevents them from moving around in the list and makes it easier to find what
you're looking for. Find the msimn entry in the list. Right click it and click
End Process. Click Yes in the dialog box warning that bad things might happen.
The msimn entry should disappear.
Find the msmsgs entry in the Image Name list. Right click that one and click End
Process. Again, click Yes on the warning dialog box.
Close the Task Manager.
Now that both the Windows Messenger and Outlook Express are closed completely,
you should be able to rename the C:\Program Files\Messenger folder.